Port test to inline expectations test

Author: egregius313

go/ql/test/library-tests/semmle/go/dataflow/flowsources/local/file/test.expected

@@ -1,3 +1,3 @@
-| test.go:6:2:6:33 | ... := ...[0] |
-| test.go:15:2:15:51 | ... := ...[0] |
-| test.go:24:2:24:37 | ... := ...[0] |
+testFailures
+invalidModelRow
+failures

go/ql/test/library-tests/semmle/go/dataflow/flowsources/local/file/test.go

@@ -3,7 +3,7 @@ package test
 import "os"
 
 func open() {
-	file, err := os.Open("file.txt")
+	file, err := os.Open("file.txt") // $ source
 	if err != nil {
 		return
 	}
@@ -12,7 +12,7 @@ func open() {
 }
 
 func openFile() {
-	file, err := os.OpenFile("file.txt", os.O_RDWR, 0)
+	file, err := os.OpenFile("file.txt", os.O_RDWR, 0) // $source
 	if err != nil {
 		return
 	}
@@ -21,7 +21,7 @@ func openFile() {
 }
 
 func readFile() {
-	data, err := os.ReadFile("file.txt")
+	data, err := os.ReadFile("file.txt") // $source
 	if err != nil {
 		return
 	}

go/ql/test/library-tests/semmle/go/dataflow/flowsources/local/file/test.ql

@@ -1,5 +1,19 @@
 import go
+import ModelValidation
+import TestUtilities.InlineExpectationsTest
 
-from DataFlow::Node source
-where source instanceof ThreatModelFlowSource
-select source
+module SourceTest implements TestSig {
+  string getARelevantTag() { result = "source" }
+
+  predicate hasActualResult(Location location, string element, string tag, string value) {
+    exists(ThreatModelFlowSource s |
+      s.hasLocationInfo(location.getFile().getAbsolutePath(), location.getStartLine(),
+        location.getStartColumn(), location.getEndLine(), location.getEndColumn()) and
+      element = s.toString() and
+      value = "" and
+      tag = "source"
+    )
+  }
+}
+
+import MakeTest<SourceTest>